1. Field of the Invention
The present invention relates to a gas insulated switchgear, and more particularly to a three-phase lumped together gas insulated switchgear in which three-phase disconnectors, grounding switches, and busbars or transmission line side conductors are housed in a common sealed vessel.
2. Description of the Related Art
Generally, high-voltage class substations are built in the suburbs of large cities, and it is desirable to miniaturize them due to skyrocketing land prices in recent years. To this end, the substations of this type can be miniaturized by constructing them by using gas insulated switchgears and by lumping three phases together. Miniaturization of the substations can also be accomplished by housing a plurality of equipment items in a common sealed vessel.
A three-phase lumped together gas insulated switchgear in such a substation according to the conventional art will now be described with reference to FIG. 6, which is a front view showing the construction of the conventional art.
In FIG. 6, reference characters 30b, 31b, and 35b denote disconnectors; reference characters 32b, 33b denote main busbars; 34b denotes a circuit breaker; and 36b denotes a container for housing cable heads.
The conventional art illustrated in FIG. 6 is a gas insulated switchgear using two three-phase main busbar disconnectors and one three-phase transmission line side disconnector.
Disconnectors 30b, 31b are connected to the circuit breaker 34b and the main busbars 32b, 33b in FIG. 6, and then the disconnectors 30b, 31b are housed in sealed vessels which are positioned above the main busbars 32b, 33b, these sealed vessels being separated from other sealed vessels in which the main busbars 32b, 33b are housed. The axes of the disconnectors 30b, 31b are arranged so as to be disposed on vertexes of a triangle. The gas insulated switchgear having such a structure is disclosed in Japanese Patent Unexamined Publication No. 62-2804.